# Question #804cf

Aug 26, 2017

Because the reaction produces hydrogen gas.

#### Explanation:

Magnesium metal will react with hydrochloric acid to produce aqueous magnesium chloride, ${\text{MgCl}}_{2}$, and hydrogen gas, ${\text{H}}_{2}$.

${\text{Mg"_ ((s)) + 2"HCl"_ ((aq)) -> "MgCl"_ (2(aq)) + "H}}_{2 \left(g\right)} \uparrow$

The hydrogen gas produced by the reaction will bubble out of the solution--this is what the up arrow added next to ${\text{H}}_{2}$ in the balanced chemical equation means--which is what you're seeing when this reaction takes place.

So it's not the magnesium metal itself that fizzles and bubbles, it's the hydrogen gas produced by the reaction.